Improvement in oil-tanks



T. SHAW-Q OIL-TANKS.

No. 194,847, Patented Sept-4,1877.

IN VENTOR ATTORNEY UNITED STATES PATENT OFFICE.

THOMAS SHAW, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN OIL-TANKS.

Specification forming part of Letters Patent No. 11!,841, dated September 4, 1877 application filed May 12, 1877.

prevent ignition 'of the oil contained therein by lightning; and I hereby declare the following to be a full,clear, and exact descriptionof the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

My invention consists in thearrangement of tanks in smoke manner as to insure a tank full of liquid, and in the provision of water- "chambers'and passageways, all for the purpose as hereinafter described.

The object of the invention is to prevent the accumulation of vapors arising from the oils, and to prevent the generation of oil vapors in hot weather, as hereinafter described.

Oil vapors, with the proper admixture of air, will ignite spontaneously at temperatures long before heat becomes visible; in fact, the feeble blue electric spark (invisible in daylight and so low in temperature that it is received on the finger with no more sensation than that produced by a single thread of a spiders web) is competent to ignite the same at every emission of the spark. All masses of material, however feeble their conducting power, serve as a medium for electrical communication, and if any portion be partially insulated, electric sparks more or less powerful are induced, and if any ignitible vapor be in its path, combustion and possible explosion is certain. It is not necessary for a thunderbolt to strike an oil-tank to ignite its contents. Any highlycharged electrical cloud passing over the tank may induce a suificient spark for the ignition of any combustible vapors, or a thunderbolt may strike the ground miles distant, and the electric discharge be conveyed by means of the piping or other metallic substances leading to or from tank. Large exposure of metallic surfaces ofi'er sure protection from the violent force of a thunderbolt, by reason of the extended metallic surface difl'usiug the electrical fluid; but there will be feeble sparks emitted in abundance, and anyone of them is competent to create a disaster by igniting oil my invention, 1 will proceed to describe its construction and operation.

On reference to the accompanying drawing," which forms part of the specification, B represents a foundation for the support of the tanks, of which R is a cylinder-tank, closed top and bottom for containing oil and water; and E is a cylinder'tank surrounding tank R, and is open at the top for retaining water above the top of tank R and for constructing a water space between the walls of tank R and tank E. A is a tank of much smaller dimensions, for containing water. L is a pipe for feeding oil into tank R; and J is a pipe for conveying oil from said tank, and I is a pipe for draining tank It of all its contents whenever desirable. K is a pipe for conveying water from tank A to tank R, and M is -a feed pipe for feeding tank A with water from any source. N is an overflow-pipe for conveyingany surplus of water 011'. O is a pipe for draining tank A of its contents whenever found necessary.

All the pipes and passage-ways are to be provided with ordinary stop-cocks for controlling the same.

The cylinder-tanks R and E are secured together firmly by ordinary stay bolts whenever the tanks have magnitude sufiicient to require the same.-

G is a metallic roof, constructed in any firm V manner, and is supported on short columns P,

secured to top of tank E, and is provided withv opening in center for ventilation, which opening is roofed at H, the roof being supported on rods S, which rods are firmly attached to roof G and reach down and are firmly secured to top of tank R, giving support against collaps ing of top of said tank R, and secure the whole in a firm manner.

The roof is not necessary for the proper 2 was."

protection or working of the tank, but the tank is rendered more complete by its addition. .7

The operation is in this wise: 0 represents oil, and D water, in tank R. The pipe 'K connectirig the oil with the water-tank, and the water-tank having a slightly-increased elevation of head of water, insure afullsupply of water to oil-tank so long as wateris supplied to water-tank, by pipe M, and the pipes I and O are closed by ordinary valves attached to same. Any oil 0 drawn ofl' from tank B through pipe J will be followed immediately bya flow of waterfrom tank A, through pipe K, into tank R, and will settle at bottom of tank by reason of superior gravity, and will gradually rise likean immense piston, forcing the oil out above it, so long as the oil is permitted to flow, until all the oil be forced out, if desired, in which case the tank will be filled with water. But when oil is permitted to flow into oil-tank through pipe L, or any suitable inlet-pipe, the oil floats above and upon the water, and gradually forces the water from tank E into tank A. Any surplus of water in tank A overflows and is led oil by pipe N, and this operation can continue until the water in tank It iseutirely displaced by oil; and these operations can both be continued at the same time or alternated with a certainty of always maintaining a full tank of liquid in oil tank R, which will prevent the accumulation of oil vapors that are liable to electric ignition,

and is the prime object of the invention.

In extremely hot weather oil-tanks exposed to the direct rays of the sun are liable to have the light oil contained therein converted into vapor of considerable tension. On this account the water-tank E is provided, which atfords a water-space between tanks E and R, and confines a bed of water, F, above tank R, and exposes a large surface of water for evaporation, interposes a medium between the oil-tank and the exterior that renders it proof against violent thunderbolts, and forbids the passing of all electric sparks by the maintenance of a liquid contact with all the inner metallic surfaces.

It will be seen that I employ two separate bodies of water, one to submerge the oil-tank and prevent the conduction of heat, electricity, or lightning to the oil-tank, or the generation of vapors; and the other body of water to elevate the oil and prevent there being space or opportunity for generation of vapors in the oil-tank.

All lightning rods in this case are useless and unnecessary, as this construction of tank is practically lightning-proof.

WhatI claim, and desire to secure by Letters Patent, is-

In lightning-proof oil tanks, the combination 'of the interior submerged oil and water tank It with the exterior water-tank E and the separate water supply tank A, the tanks E and A having no direct connecting conduit,

each tank having suitable inlet and outlet passage-ways, arranged as and for the purpose set forth. 1

, THOMAS SHAW. Witnesses:

ELIAS J. SHAW, Wm. B. HUGHES.

which lowers the temperature and 

